206681 has 6 divisors (see below), whose sum is σ = 214746. Its totient is φ = 198800.

The previous prime is 206651. The next prime is 206699. The reversal of 206681 is 186602.

206681 = T₃₈ + T₃₉ + ... + T₁₀₈.

It can be written as a sum of positive squares in only one way, i.e., 126025 + 80656 = 355^2 + 284^2 .

It is not a de Polignac number, because 206681 - 2¹⁰ = 205657 is a prime.

It is a super-2 number, since 2×206681² = 85434071522, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 206681.

It is not an unprimeable number, because it can be changed into a prime (206641) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2876 + ... + 2946.

It is an arithmetic number, because the mean of its divisors is an integer number (35791).

2²⁰⁶⁶⁸¹ is an apocalyptic number.

It is an amenable number.

206681 is a deficient number, since it is larger than the sum of its proper divisors (8065).

206681 is an frugal number, since it uses more digits than its factorization.

206681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 206681 is about 454.6218208577. The cubic root of 206681 is about 59.1244142781.

The spelling of 206681 in words is "two hundred six thousand, six hundred eighty-one".